Re: How to reduce splash back onto siding?
The way to reduce backsplash is to install a surface that absorbs the rain and gutter overflow, rather than letting it bounce back and onto the house. Wood chips or bark will absorb and redirect water. If you don't like the natural look and/or won't have plants and bushes, then gravel will work as well, though rock being hard, it will still allow some splash back.
You always want to grade the soil so that it slopes away from the structure. I'd follow the rule of thumb that is used for drain systems and concrete slabs, and that's 1/4" per foot, though if you've got good percolative soil, then you can get away with much less. The harder the soil or surface you install, the more imperative it is to have the 1/4" per foot guideline.
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